1. Field of Invention
This invention relates generally to sealed ampules for containment and dispersement of small premeasured quantities of extrusive material, and particularly to such ampules that are formed of resilient, configurationally sustaining thermoplastic polymeric material by a particular thermal process.
2. Background and Description of Prior Art
Ampules of various sorts have long been known and used for containing and dispersing smaller quantities of materials of a fluidic or somewhat fluidic nature. Such ampules in their early history were formed of rigid materials, commonly glass, with some frangible or otherwise openable or penetrable portion to allow dispersement of the contained material for use. The material carried in these early ampules generally was expressed by means of gravity and without any particular finesse, or else expression required the assistance of an auxiliary device such as a syringe with hollow needle, an applicator, a pipette or similar device that could enter the containment chamber. In the medical field syringes carrying needles were commonly used for this purpose because dispersed materials often were subsequently injected into the tissue of a patient and the needled syringe in this case served the double purpose of both dispersement of material from the ampule and injection. Such a syringe commonly was introduced into an ampule through a penetrable, resealable portion to allow use of only a part of the ampule content while leaving the remaining content in a semi-sealed and hopefully sterile condition.
As polymeric materials developed and became better known and more readily available, ampule-like packaging of extrudable materials including medicinals, chemicals and similar fluidic matter became common, especially in the form of flexible non-configurationally sustaining pouches commonly known as “pillow packs”. While pillow pack structures have developed and maintain a share of the packaging market, the polymeric type of ampule generally has remained in the traditional and habitually familiar substantially rigid non-resilient form of prior ampules or else has had a complex and resultantly expensive structure. Neither type of polymeric ampules generally have provided fine control of either product dispersement or placement without the use of ancillary apparatus, though both types of ampules undoubtedly provide improvements over prior fully rigid ampules as the deformability of the polymeric ampules allows expulsion of contained material by manually exerted force on the periphery of the ampules which is more efficient and certain than gravity motivated dispersement, while the polymeric ampules still allow use with needled syringes.
The improvement in material expulsion, however, has generally not improved control of the expulsion process nor accurate placement or distribution of the expelled product. In the case of the pillow pack type container, the control factor is often less than with prior rigid structures as a pillow pack usually is severed in some fashion by an often haphazard process to create an orifice for product dispersement that removes control potential because of the random positioning, sizing and configuration of the orifice. Because of these difficulties with control over product expulsion and placement, neither the flexible pillow packs nor resilient ampules have come into common usage with many materials, and especially finer chemical substances, medicinals and the like, notwithstanding the general economic viability of the containers for such purposes.
The instant container provides a resiliently deformable but configurationally sustaining polymeric ampule that has a body reservoir carrying an angulated spout of outwardly tapering configuration to allow fine control of both product dispersement and placement, while yet maintaining benefits of prior resilient non-configurationally sustaining ampules that require use of syringe and pipette devices.
The reservoir body of the instant ampule is formed in a cylindrical configuration from relatively thin polymeric material that is sufficiently resilient to allow fine control of contained products dispersement by force exerted by a user's fingers, normally the thumb and index finger, while yet providing sufficient rigidity and retentive memory to maintain and regain its unstressed configuration to provide a structure well suited for grasping to aid manipulation. The generally cylindrical configuration of the reservoir body has a substantially larger cross-sectional area than the largest cross-sectional area of the tapered spout to aid product flow through the spout for expulsion of high viscosity fluids, viscous gels and similar materials having centipoise values in excess of three million. This ampule configuration provides hydraulic advantage of increased pressures as the material moves from larger diameter to small diameter channels. The hydraulic force must be sufficient to overcome increased friction of the material being expelled in the narrower channel where the frictional forces increase. This dispersement of viscous material through small channels requires careful and accurate design and configuration of both the lumen and spout walls defining it to allow the ampule to withstand pressures required to move material through the lumen without either body or spout rupture or substantial configurational change. This problem has not been well addressed or dealt with in prior resiliently deformable spouted ampules and its resolution distinguishes the instant ampule both structurally and functionally.
The cylindrical configuration of the reservoir body and its formation from configuratively sustaining, resiliently deformable polymeric material provide additional secondary benefits to further distinguish the instant ampule from prior devices. With this structure one or more frangible septa may be defined in the reservoir chamber to separate two or more products stored in that space so that the septa may be ruptured and the products admixed at the time of dispersement, should this be desired. The polymeric material may also provide a transparent or translucent reservoir body wall through which contained material may be observed before and during expulsion. For light sensitive materials the reservoir body material may be rendered opaque by additives or surface coatings on either inner or outer surfaces. The reservoir body material also may incorporate various photo-blocking and ultraviolet ray blocking material including pigments which may be chosen to block light in general or specific wave lengths of the light spectrum.
The spout of the ampule for economic viability must be formed of the same material as the ampule body, but yet must define an outwardly tapering structure, with a similarly configured outwardly tapering channel. The spout must be sufficiently rigid to be configurationally sustaining when viscous material moves therethrough to fulfill its purposes. The differential strength and rigidity is accomplished by regulating the thickness of various ampule portions, generally with the spout being somewhat thicker than the reservoir body to provide the desired physical characteristics.
The material from which the ampule is formed is a thermal plastic type polymer to allow formation of the ampule the configuration specified with required economic viability. The polymeric material must allow reasonable deformation and have sufficient coherence to allow pressurized expulsion of contained material and prevent rupture during the process. For practical utility the polymeric material must have resistance to common acids, bases, peroxides and organic compounds commonly packaged in ampules, while yet having a relatively low density to strength ratio, low thermal expansion and low permeability to gases. The polymer must have thermoplastic characteristics that provide plasticity sufficient for ampule formation in a lower temperature range with the plasticity varying somewhat directly with temperature over a substantial portion of that temperature range to allow use of the formation process disclosed.
The spout provides an outwardly tapering angulated structure with a geometrically similar outwardly tapering channel defined therethrough to a sealed outer end portion. The spout may be opened by severing at various positions to provide selective orifice size and shape. The outermost end portion of the spout generally defines a channel tapering to approximately 0.01 inch by a thermal forming process as herein disclosed and thought to be novel. The tip portion of the spout may be provided with a fitting for attachment of a needle or various ancillary devices for dispersement of extruded material such as a brush, a valve, a roller ball or other similar device, for specific dispersement uses. The tip portion of the spout may be formed with one or more severable portions to provide a tear-off type seal at one or multiple axially spaced positions.
In contradistinction to forming processes for prior polymeric ampules and packages, the instant ampule is formed by pulling a thermally activated tubular blank of thermal plastic material to obtain the tapering spout configuration defining the similar tapering channel. An ampule blank is formed with the reservoir body and transition structure interconnecting a cylindrically tubular spout blank. The spout blank is heated in its medial portion to increase thermal activity in that area and the outer end of the spout blank is mechanically pulled away from the inner end which interconnects with the transition structure. As this occurs the tubular spout blank is elongated in its more plastic heated portion. As the spout blank elongates it narrows in diameter while yet maintaining its circular annular cross-sectional configuration with a proportionately sized channel of circular cross-section defined herein. It has been found that the disclosed pulling process maintains the proportional size and configuration of the channel of the tube with great integrity to diametrical sizes of 0.01 inch or less. The tube during or after the pulling process may be angulated from the axis of the original spout blank and the outer end portion of the channel sealed. The rearward reservoir body end opposite the spout may be left open and sealed in its initial formation process or it may be sealed after formation of the spout and the sealing of the spout channel if it be desired to fill the ampule from the rearward end.
It is not known that the instant drawing process of thermally activated tubular thermal plastic material has been used in forming ampules having an outwardly tapering spout of the instant type. It has not been possible to develop a cold drawing process by which a spout of the tapering nature here described may be formed in such a polymeric ampule.
My invention resides not in any one of these features individually, but rather in the synergistic combination of all of its structures and processes that give rise to the functions flowing therefrom as specified and claimed herein.